Tale Tale

Mark Eatherton

I am in the process of helping the local Habitat for Humanity troubleshoot a 15 ton AC unit that serves their offices.



There is a primary latching relay that is controlled by numeorus devices that are wired in series. Once ANY of these devices drops out (low pressure, hi pressure, low oil pressure) ALL ciruits are open, so attempting to trouble shoot the errant device by leap frogging with a DMM is virtually useless. I remember Duncan WIlson talking about a device called a Tattle Tale detector that can be wired in parallel to the safety device, and if it opens first, the device would detect it and show it as the offending device/circuit.



Does anyone know where to find one of these devices, or what its real name is?



Thanks...



Never EVER thought I'd find myself working on a forced error system,and if it weren't for the nature of the organization and the fact that they were referred to me by a local state agency that I do other work for, I probably wouldn't have gotten involved.



TIA



ME

Mark Eatherton

FOUND IT!!!

http://cgi.ebay.com/WAGNER-TT-460-TATTLE-TALE-SAFETY-CONTROL-MONITOR-42502-/200559616426



Thanks Al Gore. Without you and the internet, I'd be lost and flailing. Now, I'm just flailing :-)



ME

Tom Blackwell_2

Flash bulbs

Another trick is to use an old fashioned flash bulb-remember those? I used to keep a supply with wire leads soldered on for those systems where the culprit is elusive, such as older Carrier chillers.

don_9

tattle tales

They do there job but being like you said you have so many safetys in series you will find it still going to take some chasing on your part.

I truly hate an intermitted problem.Just a suggestion i would looked closely at the lockout relay,time delay and even the coil freezing up over time dropping your sst and locking it out on low pressure switch.

I just installed a 15 ton york condenser today and could not get power to the two stage compressor contractor.Bad board go figure.

Anyways welcome teacher we would be glad to have you on board.lets us know what you find and if we can help.



 

Ironman

Sounds Like...

Your working on a Lennox. I feel your pain. That latch relay definitely was not one of Dave's ideas that deserved an "Atta boy, Dave".



We have the Tattle Tales available at a couple of local supply houses. I would hope that one in your neck of the woods has them.

Techman

Tattle Tales

The TT is supposed to be put onto each safety.So, four safetys means four TT's. They do work!

Mark Eatherton

Thanks everyone...

This is new territory for me. I understand the logic, and have a good, no make that GREAT refrigerant mechanic, and we found the O&M manuals.



First thing I found was that the 2 stage capacity had been disconnected. Who knows why...



Reconnected and no trips (yet) to date.



The system needs replaced, but this is a cash poor organization (Habitat for Humanity main offices).



I'm looking into some newer low tech, ultra high efficiency evaporative cooling for the building called Coolerado.



ME

Mark Eatherton

Luxaire...

Now owned by Johnson Controls, and less than responsive to request for archived information...



Guess they are only interested in NEW equipment sales.



ME